Azo dye.



UNITED STATES Patented May 12, 1903.

PATENT ()FFICE.

MYRTIL KAHN, OFELBERFELD, GERMANY, ASSIGNOR TO FARBENFA- BRIKEN OF ELBERFELD 00., OF NEW YORK, N. Y., A CORPORATION on NEW YORK.

AZO DYE.

SPECIFICATION forming part of Letters Patent N 0. 727,965, dated May 12, 1903.

Application filed February 25,1903. Serial No. 145.079- (No specimens.)

(X meaning a hydrogen atom which can be replaced by halogen NO SO H, or OH such as ortho-amidophenol sulfonic acids, ortho-amidocresol sulfonic acids, ortho-amidophenol-nitro-sulfonic acids, ortho-amidophenol-chloro-sulfonic acids, ortho-amidophenol disulfonic acids, or the like, with 1 :5-dioxynaphthalene-3-sulfonic acid having the formula:

r l I The new azo dyestuffs thus obtained are dark-brown powders soluble in Water with from a reddish-violet to bluish-violet color and dyeing wool from acid-baths from bluish-- red to bluish-violet shades, turning black by a subsequent treatment with chromium compounds reacting as oxidizing agents. The black shades thus obtained possess a great fastness to the potting|process, which is a finishing process for woolen piece goods. In this process the goods are entered into boiling water and allowed to remain there until the water is cold. The goods thus assume a high degree of gloss and softness, and,according to the effect desired, the potting may be repeated several times.

In carrying out my process practically I can proceed as follows, the parts being by weight: Nineteen parts of ortho-amidophenol-para-sulfonic acid havingthe formula:

SOLE

are diazotized in the usual manner, and the resulting diazo compound is stirred into a cold solution of 26.5 parts of the acid sodium salt of the 1 :o-dioxynapthalene-3-sulfonic acid, (obtainable, e. g., by melting l :3 :5- napthalene trisulfonic acid with caustic alkalies.) A small excess of caustic-soda lye is added. After being stirred for some time the excess of caustic-soda lye is neutralized by means of hydrochloric acid, and the new dyestuff is precipitated by the addition of common salt, filtered off, and dried.

The new coloring-matter thus obtained is in the shape of the sodium salt, when dry and pulverized, a dark-brown powder soluble in water and in alcohol to a reddish-violet solution and soluble in concentrated sulfuric acid of 66 Baum with a bluish-black color,which is changed to reddish-violet on adding ice. It dyes wool from acid-bath bluish-red shades. By subsequently treating the dyed fiber with chromium compounds reacting as oxidizing agents-such as chromates, bichromates, or the like-the shades are changed to bluishblack distinguished for great fastness to the potting process. They also resist milling and washing and possess a good fastness against the action of light.

Having noW described my invention, what I claim is- 1. The herein-described new azo dyestuffs derived from ortho-amidophenol derivatives having the above-given formula, and l :5-dioxynaphthalene-3-su1fonic acid which, when in a dry state, are dark-brown powders soluble in water with from a reddish-violet to bluish-violet color and dyeing wool from acidbath from bluish-red to bluish-violet shades turning black by a subsequent treatment with chromium compounds reacting as oxidizing agents, substantially as hereinbefore described.

2. The herein-described new azo dyestufi derived from ortho-amidophenol-para-sulfonic acid and 1 :5-dioxynaphthalene-3-su1- fonic acid which, in the shape of the sodium salt, is a dark-brown powder soluble in Water and in alcohol with a reddish-Violet color; soluble in concentrated sulfuric acid of 66 Baum with a bluish-black color turning reddish-violet by the addition of ice; dyeing wool from acid-bath bluish-red shades which are changed to bluish-black by a subsequent treatment with chromium compounds reacting as oxidizing agents, substantially as described.

In testimony whereof I have signed my name in the presence of two subscribing witnesses.

OTTO KEJ'NIG, J. A. RITTERSHAUS. 

